Help! 0.0.0.0 errx???

I've had a modded xbox for about four years now... I use it for games, movies, music, etc... i've got it networked to my PC through a dlink router; i use ultrafxp for movies/tv shows, and i use qwix for games.. And i haven't had a problem with anything until now...

Yesterday, i turned on my xbox, and suddenly there's a big NOLINK! error in the bottom left corner, which turns into 0.0.0.0 errx after a while... now i can't access my xbox at all! This happened out of the blue, and i hadn't changed any of my settings or done anything differently on either the xbox or my pc..

I've done some searching around the net, and after two days now of trying to come up with a solution, i haven't been able to get anything to work... i've gone through all my settings on the xbox, enabled/disabled everything, and nothing helps... i know the cable and router still work fine, cuz my 2nd computer (laptop) gets internet from it when i plug it into the same cable... I'm lost!

Any help/advice/opinions/anything would be greatly appreciated...

thanks!